Radial component of vortex electric field force

he differential equations of motion of electrically charged bodies in an uneven vortex electric field at all possible range of velocities are obtained in the article. In the force interaction, in addition to the two components – the Coulomb and Lorentz forces – the third component of a hitherto unknown force is involved. This component turned out to play a crucial role in the dynamics of movement. The equations are written in the usual 3D Euclidean space and physical time.This takes into account the finite speed of electric field propagation and the law of electric charge conservation. On this basis, the trajectory of the electron in an uneven electric field generated by a positively charged spherical body is simulated. The equations of motion are written in vector and coordinate forms. A physical interpretation of the obtained mathematical results is given. Examples of simulations are given.

The spin-polarized electronic and magnetic properties of zinc selenide heavy doped with chromium

Atthe first stage, the structureof theZnSe crystal doped with chromium atoms (ZnCrSe)has been found by optimization procedure. At the second stage, the electronic properties of this material have been evaluated within the two approaches. The exchange-correlation functionals used here are based on the generalized gradient approximation (GGA) and the hybrid functional PBE0. The GGA approach provides the metallic state for electrons with the spin up, and for opposite spin orientation the material ZnCrSe bahaves as semiconductor, with the band gap of 2.48 eV. The hybrid functional approach also gives a gapless state for a spin up electron states, and for a spin down it provides the forbidden gap value of 2.39 eV. The magnetic moment of the unit cell, found with the two functionals, is the same and equals to 4 Bμ(Bohr magnetons). So, the calculations with the two exchange-correlation functionals provide the prediction of half-metallic properties of the ZnCrSe material, which is an interesting candidate for spintronic applications.

The principle of creating a "smart" electricity meter in electric traction networks with stochastic electromagnetic processes

Voltage and current are sharply variable random (stochastic) processes in traction networks of DC electric transport systems. As a result, electronic and hybrid electricity meters used in electric systems measure electric power with a large relative error that significantly exceeds that of their accuracy class. In this paper the principle of developing smart meters for accounting the electricity transmitted from traction substations to electric rolling stock through a traction network is proposed. Proposed ideas are developed on the basis of the random processes correlation theory. The meter operates in real time and monitors not a set of realizations of random voltage and current processes, but their deterministic characteristics, that is, time functions of mathematical expectations and variances which make up the background of its operating principle. The experimental implementation of the proposed principle has been conducted in the feeder zone of an A-B section of the GisDnieper Railway of Ukraine, where registration and processing of realizations of stochastic voltage and current processes obtained in real operation mode has been done. The ratios obtained for active and reactive power can be applied not only for traction power grids, but also for electric networks of external power supply of DC electric traction systems as the basis for the “smart meter” design.

Sputtering rate of lead, tin and germanium tellurides with low energy argon ions

Sputtering of PbTe, SnTe, and GeTe crystal samples by low-energy Ar+ ions are investigated, and the sputtering rate vsp of the studied compounds, as well as its dependence on both the composition of crystal matrix and the sputtering energy are determined. It is found that under the same conditions the sputtering rate in the sequence of GeTe-SnTe-PbTe telluride compounds increases when their average atomic weight increases. This phenomenon is explained by changes in the surface binding energy of metal atoms in lead, tin and germanium tellurides. It is shown that for all compounds the sputtering rate also increases with the increase in the sputtering energy. In the energy range from 160 to 550 eV,this increase is almost linear. The coefficients of change in the sputtering rate with energy dvsp/dE are calculated. The surface density of Ar+ ion-induced structures and the relative area of the sputtered surface covered by these structures are determined for the natural lateral surfaces of a PbTe crystal grown from melt by the Bridgman method as a function of sputtering energy. It is shown that both studied parameters decrease exponentially with increasing the sputtering energy.

Analysis of magnetic fields of electrical devices based on their circuit models

he article deals with an analysis of magnetic fields of electric machines and electromagnetic devices on the basis of their circuit mathematical models. The magnetic systems of electrical devices in these models are presented in the form of planar nonlinear magnetic circuits with lumped elements. The parameters of these elements are determined on the basis of geometric dimensions taking into account the design features of the devices and the physical parameters of the environment.

Ohmic contacts to n-type and p-type gallium antimonide whiskers

The ohmic contacts to the n-type conductivity gallium antimonide whiskers were created due to a current pulse shaper. It was established that I–V characteristics of GaSb whiskers at low temperatures are linear, regardless of the direction of current transmission. That allows using the investigated techniques to create electrical contacts and study their electrophysical characteristics. GaSb samples with a diameter of 12 μm and 20 μm were studied at temperatures 4.2 K and 77 K. A slide table with bath and microfurnace was made for welding ohmic contacts to GaSb whiskers. Gold microwire with a diameter of 30 μm was used as a contact material. The melting was carried out under the flux layer. It was revealed that the fusion is one of the most suitable methods for creating contacts to the whiskers grown by gas transport reactions.

Modeling the energy-dynamic modes of a wind farm with a battery energy storage system (BESS)

The article presents the resultsof mathematical modeling of the energy-dynamic processes of a wind farm which includes a battery energy storage system (BESS). The dependence between load capacity and energy generation capabilities of the active set of a wind power plant taking into account the energy capacity of BESS has been determined. A mathematical model of the BESS has been developed. The elaborated model is compared with two other models: a black box module and a model based on equivalent circuit model. The application of the developed model provides an opportunity to optimize the energy capacity of BESS for the specified parameters and modes of operation of the wind power plant. Using the obtained results expands the possibilities of the adequate management of energy-dynamic modes of energy systems with renewable energy sources, provides mitigation of transition processes in conditions of insufficient or excessive wind speeds and consumer loads.